Stove or furnace construction



ug 9 5 E. M. FRANKLIN 2,382,735

STOVE OR FURNACE CONSTRUCTION Filed March 6, 1944 2 Sheets-Sheet 1 Inventar N [EA/37114. Fmm/rl V Attorneys E. M. FRANKLIN 2,

STOVE OR FURNACE CONSTRUCTION iiled March 6, 1944 2 Sheets-Sheet 2 Inventor Patented Aug. 14, 1945 omen swim Tenn.

Application March 6, 1944,. Serial No. 525,240:

- 3 Gl'aims.

This invention. relates to stoves and furnaces, and the primary object of theinvention is to provide a stove or furnace construction whereby proper and complete combustion is had, and. whereby gravity feed and even burning of the fuel is effected.

'Other objects of the present invention are. to provide a stove or furnace construction wherein fuel is fed into the fire box by gravity as the fuel already in the fire box is consumed; wherein there is never a large amount of fuel in the'fire box to be coked; wherein combustion is completed in a secondary combustion chamber; wherein grate bars are air cooled internally; wherein only preheated air is used to promote combustion; and wherein the fire bed is always of substantially uniform depth.

Other objects and features of the present invention will become apparent from the following description when considered in connection with the accompanying drawings, and the invention consists in the novel form, combination and arrangement of parts hereinafter more fully described, shown in the drawings and claimed.

In the drawings, wherein like reference characters indicate corresponding parts throughout the several views:

Figure 1 is a view, partly in side elevation, and partly broken away and in vertical section, of

a stove or furnace constructed in accordance with the present invention. I

Figure 2 is a horizontal section taken on line 2.-2 of Figure 1. v

Figure 3 is a fragmentary horizontal section taken on line 3-3 of Figure 1.

Figure 4 is a fragmentary vertical section taken on line 4'4' of Figure 1.

Figure 5 is an enlarged transverse sectional view of one of the grate bars, taken on the plane of line 55 of Figure 1. Referring in detail to the drawings, 5 indicates a down-draft stack rising. from a fire box Sunder which is located an ash pit 1. A grate is provided.

leading'from' ahopperv ll whose inclined: bottom.

Walt f2: terminates: flush with the bottom of the opening 10. The hopper i2 has an air-tightlid l3, and it will be seen that the fuel may feedby gravity from the hopper I I through the opening [0 onto the inclined forward portions of the grate bars. It will also be evident that as the fuel is consumed, it will move downwardly and rearwardly by gravity onthe grate to the rear portion thereof and additional fuel will be admitted from the hopper II as the consumption of fuel on the grate proceeds.

Provided at the back of the draft stack 5 is anair intake flue l-4 having a rear inlet opening l5 at its lower end for the admission of outside air. The flue M has a top air outlet [6 constituting an air admission opening for the stack. 5 at thetop of the. latter. Extending along the sides and front of :the firebox 6 is a jacket ll forwardly through'which the grate bars extend, and this jacket H has rear endportions that extendv in-.

wardly to the sides of the flue l4 and communicate with the latter through openings [8 at the In Figure 1, it will be bottom of said flue I4 I noted that the rear end portions of the grate bars are spaced below the bottom offiue l4, while the fire box. has a front air admission opening l9 so that air may pass from the front of jacket I1 into the fire box directly under the grate. By reason of the: wall 9, this air must pass upwardly through the grate to promote combustion of the fuel thereon, after which the products of combustion pass rearwardly between the rear ends of the grate bars and the bottom. of flue I4. .The ashpit 1 has a clean-out opening 20 closed by a door 2| while the draft stack 5' has a suitable air-tight removable lid 22. Disposed rearwardly of the ash pit! is a secondary combustion chamber 23 that is also rearwardly of the grate 8 and that communicates at its upper portionwith the fire box above the grate. Any unburned gases passing from the fire box into the chamber 23 will be completely consumed in said chamber 23 before passing from the latter.

It will be notedthatthe outside air admitted to flue l4 and. in jacket l'lwill be pre-heated before passing to the fire box, and it will also be seen-that outsideair is admitted to the fire box both above and below the grate.

As shown clearly in Figure 5, the bars of gratev 8 are preferably in the form of elongated hollow tubes 24 having heat-radiating fins 25 projecting inwardly from the walls thereof. Thus, outside air is admitted to the grate bars 24 at the projecti-ng forward. ends thereof, and is discharged. at the rear ends of the same to-promote combus tion in: the secondary combustion chamber The hot products of combustion from the fire box and the chamber 23 may be utilized to generate useful heat by passing said products of combustion through a suitable heat exchanger to heat either air or water. As shown, this heat exchanger may be mounted upon the combustion chamber 23 and may be of the type including a casing 26 provided with an air or water inlet 21 at the bottom and an air or water outlet 28 at the top, both communicating with a cham ber or space 29 between headers 30 and 3! that are connected by fiues 32 through which the products of combustion pass. In other words, the products of combustion pass from the chamber 23 into the header so, then through tubular fiues 32 to header 3|. Header 3| may have a suitable smokestack or flue 33 at the'top thereof, while the tubular fiues 32 may have heat-radiatof fuel directly-above the grate, and a feed hopper for the fuel communicating at its bottom with ing fins 34. Obviously, the hot products'of comby gravity through the opening I onto the 'grate' 8' within the fire box 6, where combustion is effected by the air admitted through openings l6 and J9 from the flue l4 into stack and from the jacket I! into the fire box under the grate, --respectively. This heated air is supplied in such 'a manner as to burn the fuel from both top and bottom'of the fire bed, and when products of combustion leave the fire box they pass into the secondary combustion chamber 23 where further heated air is available from the internally cooled hollow grate bars, thereby thoroughly completing combustion. Useful heat is obtained from the heat exchanger by passage of the products of combustiontherethrough; The opening l5 may be provided with any suitable formof damper for regulating the amount of air admitted for combustion of the fuel on the grate, and as the fuel is consumed, it will move downwardly along the inclined forward portions of the grate bars so that additional fuel will be supplied from hop per H to keep a bed of substantially uniform relatively shallow depth on the grate. H

The'stack 5 facilitates the startingof the fire and removal of any accumulated clinkers, access to said stack above the grate being-had by removal of the lid 22. Ashes may be removed from theashpi't when desired by opening the door It is to be noted that a stove or furnace constructed in accordance with the present -inven-' tion will be characterized by a minimum of fuel consumption, most efficient utilization of heat generated, and most thorough consumption of fuel with little attention to thefire bed. Other advantages will be apparent tothose skilled in the art, and it is believed that the construction and operation will be entirely clear from the said fuel inlet opening and adapted to feed the fuel onto the grate as fuel is consumed on the latter. i

2. In a stove or furnace construction, a fire box having a grate therein, said grate including grate bars provided with rearwardly and downwardly inclined forward portions and consistin of open-ended tubular members having their forward upper ends projecting at the front of the fire box for the admission of outside air thereto, an ash pit below the grate and fire box, a combustion chamber rearwardly of the ash pit and communicating with the fire box above the grate, said grate bars opening at their rear lower ends into the combustion chamber, a down-draft stack rising from the fire box and having an opening in the rear wall of the upper portion thereof for the admission of outside air, said stack having an opening in the front wall thereof for the inlet of fuel directly above the grate, and a feed hopper for the fuel communicating at its bottom with said fuel inlet opening and adapted to feed the fuel onto the grate as fuel is consumed on the latter, an air intake flue arranged on the rear of and in heat exchange relation to the downdraft stack and communicating at its top with said stack through the air-admission opening of the latter, said fiue having an opening for the admission of outside air at the lower portion thereof.

,3. In a stove orfurnace construction, a fire box having a grate therein, said grate including grate bars provided with rearwardly and downwardly inclined forward portions and consisting of open ended tubular members having their forward ,u perehds projecting at the front of the fire b for'the'admission of outside air thereto, an] a pit below the grate and fire box,'a combusti chamber rearwardly of the ash pit and communieating with the fire box above the grate, said grate'bar's opening at their rear lower ends into the combustion chamber, a down-draft stack rising from the fire box and having an opening in the rear wall of the upper portion thereof for the admission of outside air, said stack having; an opening in the front wall thereof for the inlet of fuel directly above the grate, and a feed hopper for the fuel communicating at its bottom with said fuel'inlet'opening and adapted to feed the fuelflqiito thegrate as fuel is consumed onlthe latter, 'anfair intake flue arranged on the'rear of and in'h'eat exchange relation to the downdraftstackand communicatin at its top with said stack through the air admission opening of the latter, .said flue having a rear opening for the admission of outside air at thelower portion v 

